Deep ultraviolet LEDs are generally made of AlGaN material. The deep ultraviolet LED is used in the fields of sterilization, confidential communication, biochemical detection and special lighting. Hermosetting epoxy resins and organosiloxane resins are widely used as sealant materials for LED devices. These resins are spotted directly on a chip and cured to form a solid sealant. However, organic mediums in the resins easily absorbultraviolet rays, which tends to a poor transmittance and easy photolysis failure. Thus, the resin is unsuitable for using in deep ultraviolet LED package.
Therefore, fluoropolymers based on C—F have attracted widespread attention. S-type polymerized perfluoro-4-vinyloxy-1-butene with a stable end (—CF3) are manufactured. The S-type fluoropolymer has excellent ultraviolet transmittance and strong ultraviolet stability, which plays an important role in improving the performance of the deep ultraviolet LED.
However, the fluoropolymer has a poor adhesion. Thus, the fluoropolymer is difficult to be employed in the deep ultraviolet LED sandwich structures (chip-sealant-quartz lenses), and air barrier affects an optical output power and heat transfer of the deep ultraviolet LED, which causes oxygen and water vapor in the external environment to erode the chip and causes the deep ultraviolet LED to fail.
Therefore, there is room for improvement within the art.